home-experimentMeasurementsvisible-light
I know that we can measure light intensity using a simple 'light meter' and I know that 'blue light' emitted by LCD monitors is in $400-470\,\mathrm{nm}$ spectrum.
Since I have sensitive eyes, I want to measure 'blue light' in different lighting conditions.
So I'm wondering whether it is possible to measure it with simple and inexpensive home appliances? How?
This is from the Physics FAQ article that I wrote 15 years ago:
If shorter wavelengths are scattered most strongly, then there is a puzzle as to why the sky does not appear violet, the colour with the shortest visible wavelength. The spectrum of light emission from the sun is not constant at all wavelengths, and additionally is absorbed by the high atmosphere, so there is less violet in the light. Our eyes are also less sensitive to violet. That's part of the answer; yet a rainbow shows that there remains a significant amount of visible light coloured indigo and violet beyond the blue. The rest of the answer to this puzzle lies in the way our vision works. We have three types of colour receptors, or cones, in our retina. They are called red, blue and green because they respond most strongly to light at those wavelengths. As they are stimulated in different proportions, our visual system constructs the colours we see.
When we look up at the sky, the red cones respond to the small amount of scattered red light, but also less strongly to orange and yellow wavelengths. The green cones respond to yellow and the more strongly scattered green and green-blue wavelengths. The blue cones are stimulated by colours near blue wavelengths, which are very strongly scattered. If there were no indigo and violet in the spectrum, the sky would appear blue with a slight green tinge. However, the most strongly scattered indigo and violet wavelengths stimulate the red cones slightly as well as the blue, which is why these colours appear blue with an added red tinge. The net effect is that the red and green cones are stimulated about equally by the light from the sky, while the blue is stimulated more strongly. This combination accounts for the pale sky blue colour. It may not be a coincidence that our vision is adjusted to see the sky as a pure hue. We have evolved to fit in with our environment; and the ability to separate natural colours most clearly is probably a survival advantage.
The short answer to the (original) title question of "Does redshifts/blueshifts occur on Earth?" is yes, of course it does.
So why don't you notice, right?
The thing to note is that redshift from relative motion is proportional to the relative velocity divided by the speed of light.
The speed of light is 300,000 kilometers per second.
The fastest macroscopic1 objects that people accelerate go a few tens of kilometers per second.
So the ratio is of order $10^{-4}$ for the fastest human driven artifacts in existence. That is a small change.
The business with the Bezold–Brücke isn't a physics effect at all. It is---just as the quote says---a change in perception. That is, it is related to how the human visual apparatus and interpretation works. I'm cettainly not an expert in that field but it appears to just be a way of defining what is meant by "red" and "blue".
1 Of course, particle accelerators send small things to speed that approach that of light very closely, indeed. And under the right circumstances it is possible to observe very high Doppler shifts from some of these particles. But we don't generally bother because there are even more striking relativistic effect at play.
Best Answer
Might not be the cheapest option, but this has the functionality you need.
First a get a silicon photodiode, http://www.osioptoelectronics.com/standard-products/silicon-photodiodes.aspx
Then get a blue light pass filter, http://opticalfiltershop.com/product-category/edge-filter/short-wave-pass-filters/
Now you make a circuit with a 1k resistor and connect this to the circuit in series with the photodiode. You can measure the voltage drop across this resistor and because you know the resistance you can calculate the current from the voltage drop.
Alternatively, you could make or purchase a nice photodiode (transconductance) amplifier if accuracy is important, http://www.ti.com/lit/an/sboa061/sboa061.pdf
Filters that pass blue light but block other wavelengths are hard to find. Another option would be to disperse the light over different angular ranges, for example shining the light on to a prism or CD. Then only putting the diode where you see blue light. This would be similar to making your own monochromator.